The present invention relates to blind fasteners and more particularly to blind fasteners including a pin and a sleeve and having a mechanical lock structure for locking the pin and sleeve together and providing a hole fill of the openings of workpieces being secured together.
In many blind fastener applications it is desirable that the pin and sleeve be mechanically locked together to inhibit loosening, separation and/or loss of the pin through vibration, etc. Examples of such blind fasteners can be seen in the U.S. Pat. No. 4,863,325 for Two Piece Blind Fastener With Lock Spindle Construction Issued on Sep. 5, 1989 to Smith, U.S. Pat. No. 4,046,053 for Blind Rivet issued on Sep. 6, 1977 to Alvi et al, U.S. Pat. No. 3,288,016 for Blind Two-Piece Fastener issued on Nov. 29, 1966 to Reynolds, and U.S. Pat. No. 2,538,623 for Rivet Assembly issued on Jan. 16, 1951 to Keating.
It is also desirable in many applications to fill the workpiece openings. This is frequently done by radially expanding and compressing the shank of the sleeve against the surface of the workpiece openings by an expander portion of the pin. Various forms of such structures are also shown in the patents noted above.